SPD in large switchgear

brizospark · Jan 30, 2012

I was assembling a large distribution unit today. Hager type with a 500A main switch. There are 10 x 100A MCCBs going to be installed The board, MCCBs etc came in a kit, which also had a surge protection device with it. The client did specify the nee for the SPD however the SPD itself has nowhere near the terminal capacity to accommodate the 240mm main tails we are connecting in. Am I mistaken in thinking that the SPD must be installed before the main tails are connected to the main switch?

ipf · Jan 30, 2012

Just done a quote. SPD usually din rail mounted internally and fed from an outgoing MCCB.That was Schneider though.

johnboy6083 · Jan 30, 2012

I agree. The surge protection is in my experience, fed from an outgoing way.

brizospark · Jan 30, 2012

any outgoing way?

brizospark · Jan 30, 2012

and what size cable would be used etc?

Richard Burns · Jan 30, 2012

Any outgoing way, might be convenient to have it at the start to show where it is, but not necessary, you are just providing a voltage limitation, so long as it is connected OK there is nor problem.
Wire it in a cable appropriate to the breaker you have installed for connecting it, if you have installed a 16A breaker then you can use down to 1.5mm (clipped direct), etc.